Reaction product of isobutylene, sulfur monohalide and alkali metal mercaptide

ABSTRACT

A compound obtained by reacting isobutylene and a sulfur halide to produce an adduct; reacting the adduct thus produced with an alkali metal mercaptide in a nonreactive liquid medium to obtain a product comprising a compound having the structure:   AND SEPARATING THIS COMPOUND FROM SAID PRODUCT. This compound is particularly useful as an extreme pressure additive in lubricant compositions.

United States Patent [1 1 Landis et al.

[73] Assignee: Mobil Oil Corporation, New York,

22 Filed: Mar. 22, 1974 21] Appl. No; 453,610

[52] US. Cl 260/327 R; 260/139; 252/45 [51] Int. Cl. t. C07D 341/00 [58]Field of Search 260/327 R, 608, 139

[56] References Cited UNITED STATES PATENTS 7/1947 Kimball et al. 1.260/139 1 1/1972 Horodysky et al .4 260/139 Primary Examiner-Sherman D.Winters Attorney, Agent, or FirmCharles A. Huggett; Raymond W. Barclay;Benjamin 1. Kaufman [57] ABSTRACT A compound obtained by reactingisobutylene and a Dec. 9, 1975 sulfur halide to produce an adduct;reacting the adduct thus produced with an alkali metal mercaptide in anonreactive liquid medium to obtain a product comprising a compoundhaving the structure:

CH3 U";

and separating this compound from said product. This compound isparticularly useful as an extreme pressure additive in lubricantcompositions 12 Claims, N0 Drawings REACTION PRODUCT OF ISOBUTYLENE,.SULFUR MONOI'IALIDE AND ALKALI METAL MERCAP'IIDE BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates to newcompositions of matter and, more particularly, to new compositions ofmatter, especially useful as extreme pressure additives in lubricatingcompositions, such as lubricating oils and greases.

2. Description of the Prior Art It is known that extreme pressureproperties can be incorporated in lubricant compositions, such as liquidhydrocarbons and greases, by incorporating therein sulfurized olefins asextreme pressure additives. In this respect, such additives haveheretofore been found to be deficient in lacking a relatively highnon-corrosive sulfur content which is found to be particularly desirablein imparting good extreme pressure and anti-wear properties. Inadditives of this type it is also highly desirable that they be odorlessand colorless, from a commercial standpoint. These lattercharacteristics have also been found lacking in present commercialsulfurized extreme pressure additives.

SUMMARY OF THE INVENTION It has now been found that improved extremepressure properties can be imparted to lubricant compositions byincorporating therein minor amounts of a relatively high sulfurcontentadditive which, in addition, does not impart odor to the lubricant andis also colorless. As more fully hereinafter described, this novelextreme pressure additive is obtained by reacting isobutylene and asulfur halide to produce the corresponding adduct; reacting the adductthus produced with an alkali metal mercaptide in a non-reactive liquidmedium to obtain a product comprising a compound having the structure:

and separating the compound thus produced from the aforesaid reactionmixture. The compound thus produced is found to have a melting point ofapproximately 254C.

In general, the aforementioned reactions are conducted at ambienttemperature. In most operations the reactions are conducted at atemperature from about C. to about 150C. and preferably at a temperaturefrom about C. to about 60C. Insofar as the production of the adduct isconcerned, sufficient sulfur halide is employed to react with all of theisobutylene. In general, for most operations, isobutylene and the sulfurhalide are reacted in a mole ratio of from about 0.511 to about 2.521and preferably in a mole ratio of from about 1:1 to about 2:1 by weight.Insofar as the reaction between the adduct and the alkali metalmercaptide is concerned, sufficient alkali metal mercaptide is employedto react with all of the adduct. In general, for most operations, theadduct and the alkali metal mercaptide are reacted in a mole ratio offrom about 1:1 to about 1:5 and preferably in a mole ratio of from about1:1 to about 1:2.5 by weight. Any alkali metal mercaptide may beemployed for reaction with the adduct, as hereinbefore described, andmay include sodium mercaptide, potassium mercaptide, lithium mercaptide,or calcium mercaptide. Any sulfur monohalide may be used for reactionwith isobutylene and may include sulfur monochloride, or a combinationof a sulfur dihalide and elemental sulfur to produce the correspondingsulfur monohalide which may also be employed as an equivalent reagent.Any non-reactive liquid medium may be employed for carrying out thereaction between the adduct and the alkali metal mercaptide and mayinclude lower alcohols such as methanol, ethanol, propanol, butanol. Theresulting extreme pressure compound, suitable for use as an extremepressure lubricant additive is found to have a sulfur content of about50%, by weight, and is odorless and colorless. This compound representsabout 45%, by weight, of the product resulting from the reaction of theaforementioned adduct and the alkali metal mercaptide. The remainingportion of the aforementioned product comprises about 55%, by weight, amixture of unsaturated sulfides and polysulfides.

The following data and examples will serve to illustrate the markeddegree in extreme pressure improvement imparted by the novel additivesof the present invention to lubricant compositions. It will beunderstood, however, that it is not intended the invention be limited tothe particular lubricant compositions disclosed nor the particularadditive for imparting extreme pressure properties. Variousmodifications thereof can be employed and will be readily apparent tothose skilled in the art.

EXAMPLE 1 Sulfur monochloride (l013g, 7.5 moles) was charged into a 3-L.4-necked reaction flask equipped with a mechanical stirrer, condenser(drying tube attached) a thermometer, and a sub-surface gas sparger.While keeping the temperature between 4550C., isobutylene was passedover 60g of methanol into the reaction flask over an 8-hour period,during which 716g(l2.8 moles) of isobutylene was consumed. The reactionmixture was then purged at 40C. with a stream of nitrogen for 30 minutesand then filtered to yield l579g of a light amber liquid.

Sodium mercaptide, 1200g) and 1250 ml of ethanol were charged into a5-L. reaction flask fitted with a stirrer, condenser (drying tubeattached) thermometer and an addition funnel. After stirring to get agood dispersion of the solids, 620g of the above, isobutylenesulfurmonochloride adduct was added rapidly and carefully at first to attain atemperature of 45C. and then dropwise from the addition funnel. Theaddition took about 2 hours. By carefully regulating the addition, thetemperature was kept at close to 40C. and excessive foaming (H 8evolution) was avoided.

Following the aforementioned addition, the reaction mixture was heated,while stirring at 45-50C. for an additional 3 hours. After cooling toroom temperature, it was filtered, the solids washed with hexane, andthe filtrate allowed to stay overnight under house vacuum.

The solids were washed with water and ether and a water insoluble whitesolid product was collected. The solid product which precipitated fromthe filtrate was collected and washed several times with water and etherand dried. The combined solids were further purified by stirringvigorously in water and a little ether, collected and dried to yield250g of white solid product, having a sulfur content of 53%. Thisproduct was found to have the structure hereinbefore described.

An S.A.E. 90 solvent-refined Mid-Continent oil having a pour point of25F. was next subjected to the standard Four-Ball Wear Test fordetermining improvement in anti-wear properties. This test is describedin U.S. pat. No. 3,423,316. In general, in this test, three steel ballsof 52-100 steel are held in a ball cup. A fourth ball positioned on arotatable vertical axis is brought into contact with the three balls andis rotated against them. The force which the fourth ball is held againstthe three stationary balls may be varied according to a desired load.The test lubricant is added to the ball cup and acts as a lubricant forthe rotation. At the end of the test, the steel balls are investigatedfor wearscar; the extent of scarring represents the effectiveness of thelubricant as an antiwear agent. In the data of the following Table l,are shown the results obtained in which the aforementioned base stockoil was subjected to the Four-Ball Wear Test.

TABLE 1 4Ball Wear Test-Scar Diameter (mm) V2" Balls. 52-100 Steel. 60Kg. hr.

Speed Tern Ex. F 500 RPM 1000 RPM 1500 RPM 2000 RPM 2 Room 0.50 0.600.88 2.34 3 200 0.60 1.06 1.86 2.23

The above-described product of Example l was next incorporated into thebase stock lubricating oil of Table l in a concentration of 0.5%, byweight, and then subjected to the aforementioned Four-Ball Wear Test.The results obtained are shown in the following Table 11.

TAB LE 11 4-Ball Wear Test-Scar Daimeter (mm) 1%" Balls. 52-l00 Steel.60 Kg, ll: hr.

It will be apparent from the comparative data of Table l and 11 that thenovel compounds of the present invention are markedly effective asanti-wear additives. While compositions and components therefore it willbe understood, by those skilled in the art, that departure from thepreferred embodiments can be effectively made and are within the scopeof specification.

We claim:

1. A compound having the structure:

2. A process for preparing a compound having the structure recited inclaim 1, consisting essentially of reacting isobutylene and a sulfurmonohalide to produce an adduct; reacting the adduct thus produced withan alkali metal mercaptide in a non-reactive liquid medium to obtain aproduct comprising the compound described in claim 1; and separatingsaid compound from said product.

3. A process as defined in claim 2 wherein said reactions are conductedat a temperature from about 0C. to about C.

4. A process as defined in claim 2 wherein said reactions are conductedat a temperature from about 20C to about 60C.

5. A process as defined in claim 2 wherein isobutylene and the sulfurmonohalide are reacted in a mole ratio of from about 0.521 to about2.521.

6. A process as defined in claim 2 wherein isobutylene and the sulfurmonohalide are reacted in a mole ratio of from about 1:1 to about 2:1.

7. A process as defined in claim 2 wherein the adduct and the alkalimetal mercaptide are reacted in a mole ratio of from about 1:1 to about1:5.

8. A process as defined in claim 2 wherein the adduct and the alkalimetal mercaptide are reacted in a mole ratio of from about 1:1 to about1:25.

9. A process as defined in claim 2 wherein the sulfur monohalide issulfur monochloride.

10. A process as defined in claim 2 wherein the alkali metal mercaptideis sodium mercaptide.

11. A process as defined in claim 2 wherein the liquid medium is a loweralcohol.

12. A process as defined in claim 2 wherein the liquid medium is ethylalcohol.

1. A COMPOUND HAVING THE STRUCTURE:
 2. A process for preparing acompound having the structure recited in claim 1, consisting essentiallyof reacting isobutylene and a sulfur monohalide to produce an adduct;reacting the adduct thus produced with an alkali metal mercaptide in anon-reactive liquid medium to obtain a product comprising the compounddescribed in claim 1; and separating said compound from said product. 3.A process as defined in claim 2 wherein said reactions are conducted ata temperature from about 0*C. to about 150*C.
 4. A process as defined inclaim 2 wherein said reactions are conducted at a temperature from about20*C to about 60*C.
 5. A process as defined in claim 2 whereinisobutylene and the sulfur monohalide are reacted in a mole ratio offrom about 0.5:1 to about 2.5:1.
 6. A process as defined in claim 2wherein isobutylene and the sulfur monohalide are reacted in a moleratio of from about 1:1 to about 2:1.
 7. A process as defined in claim 2wherein the adduct and the alkali metal mercaptide are reacted in a moleratio of from about 1:1 to about 1:5.
 8. A process as defined in claim 2wherein the adduct and the alkali metal mercaptide are reacted in a moleratio of from about 1:1 to about 1:2.5.
 9. A process as defined in claim2 wherein the sulfur monohalide is sulfur monochloride.
 10. A process asdefined in claim 2 wherein the alkali metal mercaptide is sodiummercaptide.
 11. A process as defined in claim 2 wherein the liquidmedium is a lower alcohol.
 12. A process as defined in claim 2 whereinthe liquid medium is ethyl alcohol.